The code to parse the command line "git grep <patterns>... <rev>
[[--] <pathspec>...]" has been cleaned up, and a handful of bugs
have been fixed (e.g. we used to check "--" if it is a rev).
* jk/grep-no-index-fix:
grep: treat revs the same for --untracked as for --no-index
grep: do not diagnose misspelt revs with --no-index
grep: avoid resolving revision names in --no-index case
grep: fix "--" rev/pathspec disambiguation
grep: re-order rev-parsing loop
grep: do not unnecessarily query repo for "--"
grep: move thread initialization a little lower